A:Answer I have same plan but I never liked the idea of leasing phone, I rather own then rent and will never buy another phone from AT&T again, Bestbuy had better prices for phones and better insurance package (always get the insurance package that BB offers for all your expensive electronics stuff ) insurance from AT&T is a waste of money.
If your happy with your plan, then keep it but you can't use it at Bestbuy, that's strictly with AT&T.
Compare all AT&T phones with AT&T store / site, and check and see if you can get a better deal with Bestbuy.
I have an LG 6 and very happy with it.
Hope this helps and good luck.